The Goddard Center for Astrobiology – Theme IV

In-situ extraction, separation, and analysis of organics Theme IV activities and synergies

Paul Mahaffy

Topics

1. Organics on Mars – a MSL snapshot

2. Chemical Derivatization

3. Comet Mission Opportunities

4. Svalbard Field Campaign

5. Theme IV synergies

1.Organics on Mars – a MSL snapshot

Exploration approach “follow the water” path to understand potential for life on Mars• Meridiani Planum evidence of aqueous alteration in sulfates (MER team argues are evidence of sedimentary layers)• Mars Express OMEGA spectroscopic evidence in (Mawrth Vallis, Nili-Syrtis, and elsewhere) of phyllosilicates. These clays may have formed under wet alkaline conditions and may provide a preservation environment for biosignatures (map below from Poulet, Bibring et al., 2006 LPSC.

MSL designed to “assess a potential habitat” AO solicited scientific investigations• Objectives include a search for organics, definitive mineralogy, and light isotope measurements

1. Organics on Mars – where to look

Remote Sensing Investigations • MastCam (Imaging, Atmospheric Opacity)

• ChemCam (Chemical Composition, Imaging)

• MARDI (Landing Site Descent Imaging)

Contact Investigations• APXS (Chemical Composition)

• MAHLI (Microscopic Imaging)

Analytic Laboratory Investigations• CheMin (Mineralogy, Chemical Composition)

• SAM (Chemical/Isotopic Comp., Organics)

Environmental Investigations• DAN (Subsurface Hydrogen)

• REMS (Meteorology / UV Radiation)

• RAD (High-Energy Radiation)

SAM is a suite of 3 instruments• a quadrupole mass spectrometer (QMS)• a gas chromatograph (GC)• a tunable laser spectrometer (TLS)

SAM Core Science 1) Explore sources and destruction paths for carbon compounds

2) Search for organic compounds of biotic and prebiotic relevance including methane

3) Reveal chemical state of other light elements that are important for life as we know it on Earth

4) Study habitability of Mars by measuring oxidants such as hydrogen peroxide

5) Investigate atmosphere and climate evolution through isotope measurements of noble gases and light elements

1. Organics on Mars – MSL investigations

SMS and Housing

Tunable Laser

Spectrometer

Electronics

Solid Sample Inlets

Gas Chromatograph Chemical Separationand Processing Laboratory

Quadrupole Mass Spectrometer

Wide Range Pump

Atmospheric Inlets

Solid sample inletspenetrate through

MSL top deck

Atmospheric inletsand vents located onside of SAM box andpenetrate +Y face of

MSL WEB

1. Organics on Mars – the Sample Analysis at Mars (SAM) suite

Site Context • MastCamand ChemCam provide a geological and chemical survey for more detailed sampling by Analytical Laboratory instruments and DAN identifies potentially very interesting sites with enhanced subsurface H

Sample Screening• APXS and MAHLI chemically and with microscopic imaging screen surface materials, sampled cores or processed samples – after such screening samples can either be discarded or delivered to Analytical Laboratory

Winds and Radiation• REMS wind, temperature, and UV measurements are most relevant to SAM atmospheric sampling

• RAD provided information on surface radiation is relevant to models of transformation of organics

Definitive Mineralogy• CheMin’s elemental analysis and unambiguous identification of mineral types is highly complementary to the SAM volatile and organics analysis

1. Organics on Mars – synergy of MSL payload elements

Possible Sources of Organic Compounds on MarsExogenous Sources: infall of meteorites and interplanetary dust particles (IDPs); major

cometary impacts [IDP influx 106-107kg/yr]C-condrites are primarily kerogen-like macromolecular compounds but contain discrete pre-biotic compounds in absence of efficient destruction paths percentages of regolith could be organic

Indigenous Sources: pre-biotic/abiotic chemicals, martian life (extinct or extant) life leaves distinct chemical and isotopic patterns in organic residues

Terrestrial contamination: MSL will arrive at Mars with kilograms of organic compounds – some of fraction of which will make their way to SAM ingested samples

Transformation and preservation of organic compounds on MarsUV reaches Mars surface and destroys exposed organics (stable refractory organics survive

best)

Oxidation by hydrogen peroxide or other oxidants may transform reduced organics into metastable carboxylic acids

Galactic cosmic radiation is expected to transform organics in the near surface (~several cm) and natural radioactivity over longer time periods

1. Organics on Mars – SAM first core science goal - explore sources and destruction paths for carbon compounds

Molecules or classes of molecule most directly relevant to life

Methane: Mars Express PFS 10 ppbv average (variable over planet 0-30 ppbv), ground based observations also in progress ~90 % of terrestrial methane is likely of biological origin although abiotic production mechanisms such as serpentization reactions also contributeMethane in the Mars atmosphere has a photochemical half life of 300-600 years

Formaldehyde: Tentatively reported by Phobos; typically produced terrestrially by biogenic sources or photochemical decomposition of organic matter

Amino Acids: Building blocks of proteins and enzymes in life on Earth and often found in ancient sedimentary depostis; distinguished from meteoritic abiotically produced amino acids by type; for example, AIB (alpha-aminoisobutyric acid) is used as tracer for meteorite impacts

Amines: Ammonia derivatives essential to terrestrial life and analyzed as tracers of biological processes; also produced by thermal decarboxylation of several amino acids

Nucleobases: purines and pyrimidines that play a key role in terrestrial biochemistry; although these are also produced abiotically their source can be identified by type distribution

Carboxylic acids: predicted to be stable chemical end products of organic molecule oxidation source may be identified by examination of molecular distribution

1. Organics on Mars – SAM second core science goal - search for organic compounds of biotic and prebiotic relevance including methane

The oxidant H2O2 recently discovered by Mars Express PFS

Electrochemistry associated with Martian aeolian processes (dust devils, storms, and normal saltation) is predicted to be a significant source of H2O2

• H2O2 may precipitate to the surface and destroy near surface organics• CH4 may also be destroyed by heterogeneous processes and thus the CH4 source may be stronger than if just photochemical processes were at work• measurement of other photochemically active species is necessary to quantify the production and loss mechanisms

1. Organics on Mars – SAM’s 4th core science goal - study habitability of Mars by measuring oxidants such as hydrogen peroxide

2. Chemical Derivatization

Parameter Viking SAM Science Benefit

Pyrolysis

No. of sample cups 3 74 More samples analyzed – each cup can be used multiple times

Temperature 50, 200, 350, or 500ºC Continuous heating up to 1100ºC Identification of mineral decomposition products

Gas Chromatography

Columns Poly MPE-Tenax Molsieve 5A carbo-bond, MXT 1,5, MXT PLOT U, RTX 5 Amine, Chirasil-Val

Analysis of a wider range of organics, noble gases, VOCs, derivatized compounds, enantiomers and amines

Derivatization No Yes, MTBSTFA Transforms key organic biomarkers

Mass Spectrometer

Mass range (Da)12 - 200 2 - 535

ID of wider range of species; derivatized compounds

High throughput pumps no yes Increase in sensitivity

Static/dynamic modes Dynamic only Static or dynamic High precision noble gas isotopes

Direct EGA monitoring no yes Detect complex, less volatile species

Tunable Laser Spectrometer (TLS)

CH4 and H2O2 No TSL & MS isobaric interference

Dedicated laser channels for CH4 and H2O2

Enables detection of these important by very trace species

Isotope of C, O, H No TLS & MS isobaric interference

Isotopes of CO2, H2O, and CH4 Great improvement in precision of isotope measurements for C, O, H

2. Chemical Derivatization – Viking vs. MSL

2. Chemical Derivatization - simplified SAM derivatization process

The percent recovery of the derivatized amino acids at various transfer line temperatures relative to the standard recovery at a temperature of 280ºC. The uncertainty in the measurements shown is ± 10%. Abbreviations: ala, alanine; val, valine; ser, serine; and glu, glutamic acid.

2. Chemical Derivatization – temperature effects

OH

O

R +CF3 N

O

Si(CH3)2C(CH3)3

-

OSi(CH3)2C(CH3)3

O

R +CF3 N

O

H

.

DMF

75°C

Organic compounds

MTBSTFA

Volatile Derivative

Derivatization required to transform reactive or fragile molecules that would not have been detected by Viking instruments into species that are sufficiently volatile to be detected by GCMS

2. Chemical Derivatization – the selected MSL derivatization agent

Chromatogram obtained at the University of Paris showing the GCMS response under the same operating conditions after injection of a solution of non- derivatized amino acids (red line) and the same solution of amino acids after derivatization with MTBSTFA (black line). Only derivatized amino acids could be detected by GCMS.

2. Chemical Derivatization – amino acids

Chromatogram from the Goddard Space Flight Center (GSFC) laboratory showing GC separation and several examples of mass spectra in a standard mixture containing 14 different amino acids and 7 nucleobases after derivatization using the MTBSTFA silylation agent selected for SAM using one of the SAM flight columns.

2. Chemical Derivatization – nucleobases & amino acid standards

GCMS analysis of organic compounds extracted from an Atacama Desert soil sample after chemical derivatization in a mixture of MTBSTFA and DMF using the SAM prototype derivatization cell and GC column at GSFC (top) and after direct pyrolysis of the Atacama soil without derivatization, data provided by R. Navarro-González (bottom).

The peaks labeled X in the top chromatogram could not be identified by their mass fragmentation patterns.

2. Chemical Derivatization – Atacama extractions

GCMS analysis of an Atacama soil sample after single step extraction and derivatization with MTBSTFA and DMF at LISA.

2. Chemical Derivatization – more Atacama extractions

Arrhenius plot showing the evaporation loss rate vs. temperature of the MTBSTFA-DMF derivatization solvent mixture when exposed to Martian ambient pressure (7 torr air) inside a prototype derivatization cell. The percent mass loss of the derivatization solvent mixture 1 h after puncture at various elevated temperatures inside the MSL payload warm electronics box (WEB) is indicated by the dashed lines. To avoid significant solvent evaporation the maximum cup temperature during puncture shall be less than 9ºC.

2. Chemical Derivatization – how to make this work on MSL

3. Comet mission opportunities

Closed Ion SourceIonization Region

Open SourceIonization region

Ion Trap/ DeflectorCollimator and Dust trap

Antechamber

Quadrupole deflector

Lens System

Quadrupole Mass Analyzer

Ion Detector

Secondary Electrons

NGIMS Specifications:Neutral Gas Sampling: (1) open source/molecular beaming (2) closed source/thermalized gasPositiveIon Sampling: thermal and suprathermalIon Source: electron beam ionizationElectron Energy: 75 eVMass Range: 1 to 150 amuDetector System: dual detector pulse counting electron multipliersScan Modes: (1) programmed mass mode (2) survey (scan 1-150 amu in 1/10 or 1 amu steps (3) adaptive mode Deployment Mechanism: metal ceramic breakoff cap pyrotechnically activatedDirect Heritage: CONTOUR, Cassini INMS

3. Comet mission opportunities – currently Discovery flyby proposal

New Frontier program also provides opportunity for in situ measurements

4. Complementary activitySvalbard Field Campaign

ASTEP Mars Analogue Svalbard ExpeditionNRA 04-OSS-01

Astrobiology Science and Technology for Exploring PlanetsAndrew Steele

Geophysical Lab CIW

4. Svalbard Field Campaign

4. Planned Field Campaign - Svalbard

Objectives• examine preservation of biotic processses in Mars analog materials• test a range of analytical techniques in the field• study issues of sample integrity and cross contamination• compare field and laboratory instrumentation• instruments/techniques

CHEMINGCMS rover imaging system life detection instruments etc.

• Mars analog carbonate deposits in vertical lava conduits

•Intimately associated with olivine which is also strewn across the base of Sverrefjell

• Abiological Stromatolites

Sverrefjell

100 m

1 cm

20 µ

Sverrefjell conduit

Magnesite + dolomite cemented breccia

ALH84001 typeglobules

10 km

Bockfjord Volcanic Complex

• The worlds northernmost hot springs penetrating ~400 m permafrost

Troll Springs travertine deposit

Subglacial hot spring

10 m

10 m

Theme IV work and synergies

• Determine how to measure the history and the chemical state of organics in situ wet extraction (Glavin, Botta, Tronick, Dworkin, Buch, Coll) thermal extraction (Demick, Mahaffy, Franz) LDMS extraction (Brinckerhoff) hybrid ionization techniques (Brinckerhoff, Mahaffy)

• In situ and sample return studies and comet coma modeling actively pursuing in situ opportunities positioning members of GCA to participate in analysis of organics in sample return mission (Glavin, Dworkin)

• Comet coma modeling 3D MHD large computational scale model (Benna)

• Utilize the best available analogs to develop and calibrate instruments weathered basalts and clays, meteoritic, Atacama and other terrestrial Mars analogues (Botta, Glavin, Mahaffy, Demick, Franz, Ming, Morris, Scott, Brinckerhoff)